Radio base station power consumption is an important part of the total cost of a radio network. When there is no traffic in an area and the coverage may be served by a few other cells, e.g. umbrella cells, it may be efficient to switch some cells off or let them go into an energy saving mode.
Similarly, the energy consumption of radio networks can also be reduced if parts of, or a complete radio network (or RAT: Radio Access Technology) is switched-off in a multi-RAT environment, where multiple radio networks are covering the same area providing access via different radio network access technologies.
However, when saving power it may happen that the traffic situation suddenly changes, and that the cells/RAT in power saving mode needs to be activated to pose with the new traffic situation in the radio network. A problem when re-activating cells that are in an energy saving mode is that it is not known whether an additional demand resulting from the change in traffic can actually be served by reactivation of a particular base station. For example consider the situation where a radio base station is in an energy saving mode and that a sudden increase in traffic load is detected in the radio system. Assume further that the radio base station is not close to where the actual increase in traffic load has taken place. In this case it makes little sense to reactivate the radio base station, because the additional resource provided by reactivating the radio base station will do little good in helping to meet the demand for additional capacity. Hence, in this case the switching on of the radio base station is unnecessary.
Provided that the location of the potentially best cell to switch-on is known, another problem is to estimate is how efficient from energy consumption point of view it is to switch-on a radio base station. It may be that it requires less energy to serve the demand with the already active parts of the network.
As a result of the above, i.e. the problems of efficiently enabling power saving in cellular radio networks, typically, existing cellular radio networks generally do not reduce energy consumption of the network by switching on and off base stations. There are some special cases when the network management system of existing cellular radio networks switch on and off complete parts of the network, e.g. in shopping areas during night hours, but these scenarios are based on predefined time periods and independent of the existence and the location of actual traffic demands.
Hence, there exist a need for a method and a system that address the above and provides for improved energy savings in cellular radio systems.